Going Back and Forth A Pain

I have had my MacBook for several weeks now. It is running like a charm and has become an integral part of my workflow. However, I now find myself with a new dilemma--keeping data synced between systems. I still use my home PC for some things, but also use the laptop for many things. I'll often check email on one machine or the other--which causes me to lose track of where-I-stored-what-email-where... Throw another device into the mix--my Motorola Q (now set up with POP3 access)--and I've got emails scattered all over the place.

The same problem applies to my school projects/papers, or really any document for that matter. I have different versions of things floating around and am quickly losing track of where the latest versions are. This is becoming a really annoying problem. I'm at the point now where I feel I need to just scrap my home PC altogether and turn it into a server, but I like having to use Windows when I need to and having a little bit bigger screen than the laptop. I have Parallels on the Mac now, but unfortunately still don't have Vista installed.

Anyone else have this problem? How do you deal with it?